The tweeter that is in the X3 is one of the very best in the world, not surprised at all that it's a major step up over M3.
Same with OB bass. When you first hear OB bass on a speaker like the original M3 you are usually struck by the amount of musical detail and clarity in the bass that's just not possible with a regular box style speaker with most rooms.
BUT, with a speaker like the X3, you add a powered woofer and suddenly you're like "oh, THERE'S the slam I was missing before". Yeah, that thing is a great design, can't wait to hear them next month at RMAF.